Actions by the D.C. Zoning Commission last week cleared the way for several office, retail and residential developments. Among projects receiving approval were:

An office and retail complex at 20th and L streets NW.

A residential and retail development on the site of the old Thompson's Dairy Building at 11th and U streets NW.

A complex of 150 units of low- and moderate-income housing for the elderly at Bladensburg Road and Florida Avenue.

A chancery on the grounds of Firenze, an Albermarle Street estate owned by the Italian Embassy.

The Zoning Commission actions must be reviewed by the National Capital Planning Commission before they become final.

The Lafayette Center project at 20th and L streets is a Planned Unit Development (PUD). In a PUD, the Zoning Commission allows developers to build larger structures than ordinarily allowed in return for public amenities and Zoning Commission control over many aspects of development.

Lafayette Center will consist of three office buildings linked by a covered atrium that will be open to the public. In approving the project, which will be built in three phases, the commission ordered that at least 20,000 square feet on the ground floor be devoted to retail stores and that the complex contain at least one outdoor restaurant.

In the Italian chancery case, also a PUD, the commission specified that the mansion be maintained for embassy use and that new buildings on the estate not exceed 40 feet in height.

Zoning of the 57,000 square feet at 11th and U streets, once occupied partly by Thompson's Dairy and partly by an annex to Children's Hospital, was changed from industrial to a combination of residential and commercial. Developers Semih Ustun and Barrett Linde told the commission at a hearing April 19 that they planned a complex containing 65 to 100 housing units plus retail space along U Street.

The D.C. Department of Housing and Community Development, which plans a complex of 150 apartments for low- and moderate-income elderly residents in the H Street Urban Renewal Area at Bladensburg Road and Florida Avenue NE, received a zoning change that will allow a 10-story building on the site.

In other action, the commission postponed decisions on a request by the Iranian Embassy to establish a chancery in the 2500 block of 30th Street NW and on a PUD requested by the American Trucking Association (ATA) for an office development at 17th and O street NW.

The commission will hold another hearing on the Iranian request, which neighbors opposed, on June 14. In the ATA case, the commission asked the association to include some residential units in the development. The ATA residential proposal will be the subject of a Zoning Commission hearing at 1:30 p.m. today.